U.S. patent application number 13/595784 was filed with the patent office on 2014-02-27 for air-cooled optical transceiver module system.
This patent application is currently assigned to Avago Technologies General IP (Singapore) Pte. Ltd.. The applicant listed for this patent is Laurence R. McColloch, David J.K. Meadowcroft, Paul Yu. Invention is credited to Laurence R. McColloch, David J.K. Meadowcroft, Paul Yu.
Application Number | 20140056592 13/595784 |
Document ID | / |
Family ID | 50069787 |
Filed Date | 2014-02-27 |
United States Patent
Application |
20140056592 |
Kind Code |
A1 |
McColloch; Laurence R. ; et
al. |
February 27, 2014 |
AIR-COOLED OPTICAL TRANSCEIVER MODULE SYSTEM
Abstract
In an opto-electronic system having one or more optical
transceiver modules and an enclosure, air is forced through the
interior of the transceiver module to dissipate heat generated by
the opto-electronic and electronic elements.
Inventors: |
McColloch; Laurence R.;
(Santa Clara, CA) ; Meadowcroft; David J.K.; (San
Jose, CA) ; Yu; Paul; (Mountain View, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
McColloch; Laurence R.
Meadowcroft; David J.K.
Yu; Paul |
Santa Clara
San Jose
Mountain View |
CA
CA
CA |
US
US
US |
|
|
Assignee: |
Avago Technologies General IP
(Singapore) Pte. Ltd.
SINGAPORE
SG
|
Family ID: |
50069787 |
Appl. No.: |
13/595784 |
Filed: |
August 27, 2012 |
Current U.S.
Class: |
398/135 ;
29/428 |
Current CPC
Class: |
Y10T 29/49826 20150115;
H04B 10/40 20130101 |
Class at
Publication: |
398/135 ;
29/428 |
International
Class: |
H04B 10/02 20060101
H04B010/02; B23P 11/00 20060101 B23P011/00 |
Claims
1. A method of operation in an optical transceiver module system,
comprising: providing an enclosure having a plurality of bays, each
bay having an elongated shape extending substantially along a
longitudinal axis, each bay having a bay electrical connector;
plugging a transceiver module into one of the bays, the transceiver
module having an electronics subassembly, an optics subsystem, and
an elongated rectangular transceiver module housing assembly
extending between a nose end and a tail end of the transceiver
module, the electronics subassembly comprising a light source and a
substrate having a plurality of signal conductors and a generally
planar shape elongated in a direction corresponding to the
longitudinal axis; mating the electronics subassembly with the bay
electrical connector of the one of the bays in which the
transceiver module is inserted, the electronics subassembly
receiving electrical signals via the bay electrical connector;
connecting a fiber-optic cable connector to an optical receptacle
at the nose end of the transceiver module; activating the light
source in response to the electrical signals, the light source
generating an optical beam and heat in response to activation; the
optics subsystem redirecting the optical beam into the optical
receptacle; and a cooling fan mounted in the enclosure conveying a
flow of air into a first airflow opening in the transceiver module
housing, the flow of air passing through an interior cavity portion
of the transceiver module housing assembly in a direction
corresponding to the longitudinal axis and past the light source,
the flow of air exiting the transceiver module housing through a
second airflow opening in the transceiver module housing.
2. The method of claim 1, wherein the step of conveying a flow of
air comprises conveying the flow of air in a direction
corresponding to the longitudinal axis through one of the first and
second airflow openings disposed at the nose end of the transceiver
module.
3. The method of claim 2, wherein the step of conveying a flow of
air comprises conveying the flow of air in the direction
corresponding to the longitudinal axis past a heat sink attached to
an opto-electronics assembly mounted on the substrate.
4. The method of claim 3, wherein the step of conveying a flow of
air comprises conveying the flow of air in the direction
corresponding to the longitudinal axis past a TO-can package in
which the light source is mounted.
5. The method of claim 4, wherein the step of conveying a flow of
air comprises conveying the flow of air past a driver integrated
circuit coupled to a surface of a printed circuit board of the
electronics subassembly, and wherein the electronics subassembly
comprises a printed circuit board, the TO-can package, and a flex
circuit, the flex circuit coupling signals between the TO-can
package and the printed circuit board.
6. The method of claim 1, wherein the nose end of the transceiver
module is disposed outside the enclosure when the transceiver
module is fully plugged into the one of the bays, and wherein the
step of conveying a flow of air comprises conveying the flow of air
in a direction corresponding to the longitudinal axis through the
one of the first and second airflow openings disposed at the nose
end of the transceiver module.
7. The method of claim 6, wherein: the step of conveying a flow of
air comprises conveying the flow of air through the one of the
first and second airflow openings in a metal portion of the
transceiver module housing assembly at the nose end of the
transceiver module; and the step of inserting a transceiver module
into one of the bays comprises a user grasping a plastic portion of
the transceiver module housing assembly at the nose end of the
transceiver module forward of the metal portion.
8. The method of claim 1, wherein the nose end of the transceiver
module is disposed outside the enclosure when the transceiver
module is fully plugged into the one of the bays, and wherein the
step of conveying a flow of air comprises conveying the flow of air
in a direction transverse to the longitudinal axis through the one
of the first and second airflow openings disposed at the nose end
of the transceiver module.
9. The method of claim 8, wherein: the step of conveying a flow of
air comprises conveying the flow of air through the one of the
first and second airflow openings in a metal portion of the
transceiver module housing assembly at the nose end of the
transceiver module; and the step of inserting a transceiver module
into one of the bays comprises a user grasping a plastic portion of
the transceiver module housing assembly at the nose end of the
transceiver module forward of the metal portion.
10. The method of claim 8, wherein the step of conveying a flow of
air comprises conveying the flow of air through an aperture in the
substrate between an upper side of the substrate and a lower side
of the substrate, and wherein the first and second airflow openings
are disposed on opposite sides of the substrate.
11. The method of claim 10, further comprising the step of
conducting heat through a thermally conductive path between a
driver integrated circuit and the metal portion of the transceiver
module housing assembly.
12. The method of claim 1, wherein the enclosure comprises a
plurality of front panel openings, each front panel opening
adjacent to one of the bays and adjacent to the nose end of the
transceiver module when the transceiver module is fully plugged
into the one of the bays, and wherein the step of conveying a flow
of air comprises conveying the flow of air through the enclosure
between one of the first and second airflow openings and the front
panel opening.
13. The method of claim 12, wherein the bay electrical connector
comprises an upper connector having a housing in which upper
connector fingers are enclosed, a lower connector having a housing
in which lower connector fingers are enclosed, and exposed
electrical signal conductors extending between the upper connector
and lower connector in a direction transverse to the direction
corresponding to the longitudinal axis, and wherein the step of
conveying a flow of air comprises conveying the flow of air past
the exposed electrical signal conductors.
14. The method of claim 1, further comprising the step of
conducting heat through a thermally conductive path between a
driver integrated circuit and a metal portion of the transceiver
module housing assembly.
15. An optical transceiver module system, comprising: an enclosure
having a plurality of bays, each bay having an elongated shape
extending substantially along a longitudinal axis, each bay having
a bay electrical connector; a cooling fan in the enclosure
configured to convey air in a direction corresponding to the
longitudinal axis; a transceiver module plugged into one of the
bays, the transceiver module having a nose end and a tail end and
extending between the nose end and the tail end in a direction
corresponding to the longitudinal axis, the transceiver module
comprising: an electronics subassembly comprising a light source
and a substrate, the substrate having a plurality of signal
conductors and a generally planar shape elongated in the direction
corresponding to the longitudinal axis, the electronics subassembly
mated with the bay electrical connector of the one of the bays into
which the transceiver module is plugged; an elongated rectangular
transceiver module housing assembly extending between the nose end
and the tail end of the transceiver module and having at least one
optical receptacle disposed at the nose end of the transceiver
module housing assembly for receiving a fiber-optic cable plug
connector, the transceiver module housing assembly having a first
airflow opening and a second airflow opening separated by an
interior cavity portion of the transceiver module housing extending
in a direction corresponding to the longitudinal axis, wherein the
light source is mounted in the interior cavity portion of the
transceiver module housing between the first airflow opening and
the second airflow opening; and an optics subsystem in the
transceiver module housing configured to redirect an optical beam
between the light source and the optical receptacle.
16. The optical transceiver module system of claim 15, wherein one
of the first and second airflow openings is disposed at the nose
end of the transceiver module and has a flow axis oriented in a
direction corresponding to the longitudinal axis.
17. The optical transceiver module system of claim 16, wherein the
electronics subassembly comprises an opto-electronics subassembly
mounted to the substrate, an optical axis of the light source
oriented in a direction corresponding to the longitudinal axis, and
further comprising a heat sink attached to the opto-electronics
assembly and disposed along the flow axis of the one of the first
and second airflow openings.
18. The optical transceiver module system of claim 17, wherein the
opto-electronics subassembly comprises a printed circuit board, a
TO-can package in which the light source is mounted, and a flex
circuit, the flex circuit coupling signals between the TO-can
package and the printed circuit board.
19. The optical transceiver module system of claim 18, further
comprising a driver integrated circuit electrically coupled to the
light source and to at least a portion of the signal conductors,
the driver integrated circuit coupled to a surface of the printed
circuit board and disposed along the flow axis of the one of the
first and second airflow openings.
20. The optical transceiver module system of claim 15, wherein the
nose end of the transceiver module is disposed outside the
enclosure when the transceiver module is fully plugged into the one
of the bays, and one of the first and second airflow openings is
disposed outside the enclosure and has a flow axis oriented in a
direction corresponding to the longitudinal axis.
21. The optical transceiver module system of claim 20, wherein the
nose end of the transceiver module comprises a metal portion of the
transceiver module housing assembly having the one of the first and
second airflow openings, and a plastic portion having the optical
receptacle forward of the metal portion.
22. The optical transceiver module system of claim 15, wherein the
nose end of the transceiver module is disposed outside the
enclosure when the transceiver module is fully plugged into the one
of the bays, and one of the first and second airflow openings is
disposed outside the enclosure and has a flow axis oriented in a
direction transverse to the longitudinal axis.
23. The optical transceiver module system of claim 22, wherein the
nose end of the transceiver module comprises a metal portion of the
transceiver module housing assembly having the one of the first and
second airflow openings, and a plastic portion having the optical
receptacle forward of the metal portion.
24. The optical transceiver module system of claim 23, wherein the
substrate has an aperture between an upper side of the substrate
and a lower side of the substrate, and the first and second airflow
openings are disposed on opposite sides of the substrate.
25. The optical transceiver module system of claim 24, further
comprising a driver integrated circuit coupled through a thermally
conductive path to the metal portion of the transceiver module
housing assembly.
26. The optical transceiver module system of claim 15, wherein the
enclosure comprises a plurality of front panel openings, each front
panel opening adjacent to one of the bays and adjacent to the nose
end of the transceiver module when the transceiver module is fully
plugged into the one of the bays, the enclosure providing an air
flow passage between one of the first and second airflow openings
and the front panel opening when the transceiver module is fully
plugged into the one of the bays.
27. The optical transceiver module system of claim 15, wherein the
bay electrical connector comprises an upper connector having a
housing in which upper connector fingers are enclosed, a lower
connector having a housing in which lower connector fingers are
enclosed, and exposed electrical signal conductors extending
between the upper connector and lower connector in a direction
transverse to the direction corresponding to the longitudinal axis,
the exposed electrical signal conductors defining an air flow
passage to one of the first and second airflow openings when the
transceiver module is fully plugged into the one of the bays.
28. The optical transceiver module system of claim 15, further
comprising a driver integrated circuit coupled through a thermally
conductive path to the metal portion of the transceiver module
housing assembly.
Description
BACKGROUND
[0001] In an optical communication system, it is typically
necessary to couple an optical fiber to an opto-electronic
transmitter, receiver or transceiver device and to, in turn, couple
the device to an electronic system such as a switching system or
processing system. These connections can be facilitated by
modularizing the transceiver device. Various transceiver module
configurations are known. For example, the optical transceiver
module 10 illustrated in FIG. 1 has a standard configuration or
form commonly referred to as a Small Form Factor (SFF) or
SFF-Pluggable (SFP) format. Transceiver module 10 includes a
metallic module housing 12 in which are housed opto-electronic
elements, optical elements, and electronic elements, such as one or
more light sources (e.g., lasers), light sensors, lenses and other
optics, digital signal driver and receiver circuits, etc. The front
end or nose 14 of transceiver module 10 further includes a
transmitter receptacle 16 and a receiver receptacle 18 into which
optical fiber cables (not shown) are pluggable. The optical cable
plug or connector body (not shown) can be of the standard type
known as an LC connector, which has a substantially square profile
corresponding to the shape of receptacles 16 and 18. Although not
shown in FIG. 1 for purposes of clarity, transceiver module 10 can
be plugged into a bay in the chassis or cage of an electronic
system by inserting the rear end of transceiver module 10 into a
bay opening in the cage and latching transceiver module 10 in
place. A bail latch 20 facilitates latching transceiver module 10
and, when flipped to an extended position (not shown), serves as a
handle by which a person can grip transceiver 10 to extract it from
the cage.
[0002] Transceiver module cooling is a concern in the art. When
transceiver 10 is plugged into a cage bay, the metallic module
housing 12 is in contact with metallic walls of the cage bay. The
heat emitted by the electronics and opto-electronics in transceiver
module 10 in operation is commonly conducted away from transceiver
module 10 by the metal walls of the cage bay. Heat sinks can be
included in the cage to help dissipate the conducted heat. The cage
is commonly mounted within a larger box-like enclosure containing
electronics with which the plugged-in transceiver module 10
communicates electrical signals when in operation.
SUMMARY
[0003] Embodiments of the present invention relate to an optical
transceiver module system and method of operation in which a flow
of air through the interior of the transceiver module dissipates
heat generated by the opto-electronic and electronic elements. In
an exemplary embodiment, an optical transceiver module system
comprises an enclosure, a cooling fan in the enclosure, and at
least one transceiver module plugged into one of the enclosure
bays. The bays have an elongated shape corresponding to that of the
transceiver. Each bay extends substantially along a longitudinal
axis and has a bay electrical connector at the end opposite that
into which the transceiver module is plugged. The cooling fan is
configured to convey air in a direction corresponding to (e.g.,
parallel or substantially parallel to) the longitudinal axis. The
transceiver module extends between a nose end and a tail end in a
direction corresponding to the longitudinal axis. The transceiver
module includes a transceiver module housing assembly, an
electronics subassembly, and an optics subsystem. The electronics
subassembly includes a light source and a substrate. The substrate,
which can be, for example, a printed circuit board, has a number of
signal conductors, such as, for example, circuit traces.
Accordingly, the substrate has a generally planar shape elongated
in the direction corresponding to the longitudinal axis. The
electronics subassembly mates with the bay electrical connector of
the bay into which the transceiver module is plugged. The
transceiver module housing assembly has a substantially rectangular
profile and extends in a longitudinal direction between the nose
end and the tail end of the transceiver module. The transceiver
module housing assembly has at least one optical receptacle
disposed at the nose end for receiving a fiber-optic cable plug
connector. The optics subsystem is configured to redirect an
optical beam between the light source and the optical receptacle.
The transceiver module housing assembly has a first airflow opening
and a second airflow opening separated or spaced apart in a
direction corresponding to the longitudinal axis by an interior
cavity portion of the transceiver module housing. The light source
is mounted in the interior cavity portion between the first airflow
opening and the second airflow opening.
[0004] An exemplary method of operation comprises providing the
above-referenced enclosure and transceiver module, and inserting
the transceiver module into one of the bays such that the
electronics subassembly mates with the bay electrical connector and
the electronics subassembly is configured to receive electrical
signals via the bay electrical connector. A fiber-optic cable
connector is connected to an optical receptacle at the nose end of
the transceiver module. The light source is activated in response
to the electrical signals and, as a result, generates not only an
optical beam but also heat. The cooling fan conveys a flow of air
into the first airflow opening in the transceiver module housing.
The flow of air passes through the interior cavity portion of the
transceiver module housing assembly in a direction corresponding to
the longitudinal axis and passes the light source, from which the
air flow picks up excess heat. The heated flow of air then exits
the transceiver module housing through the second airflow
opening.
[0005] Other systems, methods, features, and advantages will be or
become apparent to one with skill in the art upon examination of
the following figures and detailed description. It is intended that
all such additional systems, methods, features, and advantages be
included within this description, be within the scope of the
specification, and be protected by the accompanying claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The invention can be better understood with reference to the
following drawings. The components in the drawings are not
necessarily to scale, emphasis instead being placed upon clearly
illustrating the principles of the present invention.
[0007] FIG. 1 is a perspective view of an optical transceiver
module in accordance with the prior art.
[0008] FIG. 2 is a schematic illustration of an optical transceiver
module system in accordance with exemplary embodiments of the
invention.
[0009] FIG. 3 is a perspective view of an optical transceiver
module system in accordance with a first exemplary embodiment of
the invention.
[0010] FIG. 4 is a schematic illustration of an optical transceiver
module of the system of FIG. 3.
[0011] FIG. 5 a rear perspective view of an optical transceiver
module of the system of FIG. 3.
[0012] FIG. 6 is a sectional view taken on line 6-6 of FIG. 3.
[0013] FIG. 7 is a front perspective view of an optical transceiver
module system in accordance with a second exemplary embodiment of
the invention.
[0014] FIG. 8 is a sectional view taken on line 8-8 of FIG. 7.
[0015] FIG. 9 is a rear perspective view of an optical transceiver
module of the system of FIG. 7.
[0016] FIG. 10 is a front elevation view of an optical transceiver
module of the system of FIG. 7.
[0017] FIG. 11 is a bottom perspective view of an optical
transceiver module of the system of FIG. 7.
[0018] FIG. 12 is a front perspective view of an optical
transceiver module system in accordance with a third exemplary
embodiment of the invention.
[0019] FIG. 13 is a rear perspective view of the optical
transceiver module system of FIG. 12.
[0020] FIG. 14 is rear elevation view of the module cage of the
system of FIG. 13, with the rear wall of the module cage removed to
reveal the interior.
[0021] FIG. 15 is a rear perspective view of a module bay
electrical connector of the module cage of FIG. 14.
[0022] FIG. 16 is a front perspective view of a module bay
electrical connector of the module cage of FIG. 14.
[0023] FIG. 17 is a front perspective view of one of the plurality
of connector slices of the module bay electrical connector of FIG.
16.
[0024] FIG. 18 is a perspective view of a transceiver of the
optical transceiver module system of FIG. 12.
[0025] FIG. 19 is a sectional view taken on line 18-18 of FIG.
12.
[0026] FIG. 20 is an enlargement of a portion of FIG. 19.
DETAILED DESCRIPTION
[0027] As illustrated in FIG. 2, in an illustrative or exemplary
embodiment of the invention, a transceiver module system 22
comprises or includes one or more transceiver modules 24 that are
plugged into one or more corresponding module bays 26 of a module
cage 28. The forward ends or nose ends 30 of transceiver modules 24
extend outside of module cage 28 when transceiver modules 24 are
fully plugged in to module cage 28. Although not shown in FIG. 2
for purposes of clarity, each rearward or tail end 32 of a
transceiver module 24 electrically and mechanically mates with an
electrical connector in the module bay 26 into which it is plugged.
As used herein for reference purposes, the term "forward" means
closer to nose end 30 than to tail end 32, and the term "rearward"
means closer to tail end 32 than to nose end 30. Transceiver
modules 24 have substantially rectangular exterior profiles that
correspond to the substantially rectangular interior profiles of
the module bays 26 that receive transceiver modules 24, thereby
providing a snug fit of each transceiver module 24 within a module
bay 26. Transceiver modules 24 can be inserted into module bays 26
and removed from module bays 26 in an essentially conventional
manner. As persons skilled in the art understand how transceiver
modules 24 can be plugged in and removed, such details are not
further described herein for purposes of clarity.
[0028] Module cage 28 is mounted within an outer enclosure 34.
Although not shown for purposes of clarity, outer enclosure 34
encloses an electronic system with which transceiver modules 24 are
interfaced by virtue of being plugged into module cage 28. That is,
electrical signals are communicated between transceiver modules 24
and such an electronic system via the above-referenced electrical
connectors (not shown in FIG. 2) in the module bays 26.
[0029] A cooling fan 36 is mounted within outer enclosure 34 and
powered by a suitable power supply (not shown) that also powers
transceiver modules 24 and the above-referenced electronic system
in outer enclosure 34. In FIG. 2, generalized air flows are
represented by arrows 38, 40, 42, 44, 46 and 48. The air flows are
depicted in generalized form in FIG. 2 in that arrows 38-48 are
intended only to convey a general sense of the directions in which
air flows with respect to other elements and not to convey any
specific type, quantity, strength or other quality or aspect of the
flowing air. In some (not necessarily all) embodiments, cooling fan
36 draws air from the exterior of outer enclosure 34 into the
interior of outer enclosure 34 (as represented by arrows 38) and
directs a flow of air (as represented by arrow 40) toward the rear
of module cage 28. Nevertheless, in other embodiments (not shown)
such a cooling fan can draw air in a direction opposite that which
is described and depicted herein (e.g., expel air from the interior
of outer enclosure 34 to the exterior of outer enclosure 34). Note
that the direction in which air is depicted in FIG. 2 flowing
through outer enclosure 34 is substantially in a direction
corresponding to (e.g., parallel to) the longitudinal axes 50 of
the various transceiver modules 24 plugged into module cage 28.
[0030] Although not shown in the schematic representation of FIG. 2
for purposes of clarity, one or more walls of outer enclosure 34
have apertures or holes (e.g., a grille) through which the airflows
represented by arrows 38 can occur. Although similarly not shown in
FIG. 2 for purposes of clarity, the air within outer enclosure 34,
flowing in the direction described above, enters module bays 26
through similar apertures or holes (e.g., a grille) in the rear
wall of module cage 28, as represented by arrows 42.
[0031] As described below with regard to a number of exemplary
embodiments (i.e., more specific implementations of the exemplary
embodiment shown in FIG. 2), air enters each transceiver module 24
and flows through portion of it. Air exits each transceiver module
24 through apertures or holes (not shown in FIG. 2 for purposes of
clarity) in one or more of at least three directions: a direction
corresponding to (e.g., parallel to) longitudinal axis 50 (as
represented by arrows 44); an upward direction substantially
transverse to longitudinal axis 50 (as represented by arrow 46);
and a downward direction substantially transverse to longitudinal
axis 50 (as represented by arrow 48). It should be noted that in
some embodiments a transceiver 24 can expel or exhaust air in a
certain combination of one or more of these directions, while in
other embodiments a transceiver can expel or exhaust air in other
combinations of one or more of these directions.
[0032] Although the embodiments represented by FIG. 2 include the
combination of a module cage 28 and cooling fan 36 within an outer
enclosure 34, with the front of module cage 28 mounted in a front
panel of outer enclosure 34, other embodiments (not shown) can
instead include a structure that combines aspects of module cage
28, cooling fan 36 and outer enclosure 34. For example, in another
embodiment a structure similar to module cage 28 but with a cooling
fan attached to its rear wall can be provided such that outer
enclosure 34 can be omitted. The term "enclosure" as used herein
encompasses within its scope of meaning not only the structures
described herein but also such alternative structures. Also, unless
indicated otherwise in a specific instance, the term "in" is
intended to encompass within its scope of meaning both "in" and
"on," and the term "on" is intended to encompass within its scope
of meaning both "on" and "in." Similarly, the phrase "attached to"
and similar connection or attachment phrases also encompass
attached or otherwise connected in. For example, unless indicated
otherwise, a first element mounted on or attached to a second
element in one embodiment can alternatively be mounted in or
attached in the second element in another embodiment.
[0033] As illustrated in FIG. 3, in an exemplary embodiment an
optical transceiver module system 52 includes at least one
transceiver module 54 and a module cage 56 mounted in a front panel
(wall) of an outer enclosure 58. Fan 36 (FIG. 2) is mounted within
outer enclosure 58 but not shown in FIG. 3 for purposes of clarity.
Although not shown for purposes of clarity, the rear wall of module
cage 56 has a grille or array of apertures to admit airflow in the
manner described above with regard to FIG. 2. Transceiver module 54
and module cage 56 more specifically embody or implement the
generalized transceiver module 24 and module cage 28, respectively,
described above with regard to FIG. 2.
[0034] As illustrated in FIG. 4, transceiver module 54 includes an
opto-electronic subassembly 60 mounted a printed circuit board
(PCB) substrate 62. Opto-electronic subassembly 60 and PCB
substrate 62 together define an electronics subassembly.
Transceiver module 54 further includes optics 64 and an optical
fiber 66. Opto-electronic subassembly 60 includes a TO-can package
67 in which a light source 68, such as a laser, and a light
detector 70, such as a photodiode are mounted. Opto-electronic
subassembly 60 further includes a flex circuit 72 that couples
electrical signals between the TO-can package 67 and PCB substrate
62 via electrical contact pins 71 on the header of TO-can package
67. Optics 64, which can include lenses and reflectors, redirect an
optical beam (signal) emitted from light source 70 into an end of
optical fiber 66 and redirect an optical beam (signal) emitted from
the end of optical fiber 66 onto light detector 70. As persons
skilled in the art are capable of providing suitable optics 64,
details of optics 64 are not further described herein for purposes
of clarity.
[0035] As illustrated in FIGS. 5-6, the forward or nose end of
transceiver module 54 has two openings 74 and 76 aligned along flow
axes 78 and 80, respectively. Note that flow axes 78 and 80 are
oriented in a direction corresponding to longitudinal axis 50 (FIG.
2). In operation, the airflow enters module cage 56 (FIG. 6)
through apertures 81 as described above with regard to FIG. 2. The
airflow enters the transceiver module housing assembly 82 (FIG. 5)
at the open rear or tail end of transceiver module 54. The walls of
transceiver module housing assembly 82 can be made of a suitable
metal for mechanical strength and thermal conductivity. The air
flows through the interior cavity of transceiver module housing
assembly 82 in a direction substantially corresponding to
longitudinal axis 50 and exits transceiver module housing assembly
82 through openings 74 and 76. As the air flows through the
interior cavity 83 of transceiver module housing assembly 82, the
air passes the above-described (FIG. 4) electronics subassembly,
including TO-can package 67. The operation of light source 68 (FIG.
4) causes TO-can package 67 to become hot and radiate heat into the
surrounding air. The airflow carries away some of this radiated
heat and expels it through openings 74 and 76. Heat sinks 84 are
attached to TO-can package 67 to facilitate heat transfer to the
airflow.
[0036] A driver integrated circuit 85 is mounted on a portion of
flex circuit 72 that is in turn mounted on PCB substrate 62. As
persons skilled in the art understand, driver integrated circuit 85
provides electrical signals to light source 68 in response to
signals received from the external electronic system within outer
enclosure 58. Heat radiating from driver integrated circuit 85 into
the surrounding air is also dissipated from the interior cavity of
transceiver module housing assembly 82 by the above-described
airflow. In addition, driver integrated circuit 85 is coupled
through a thermally conductive path through PCB substrate 62 to the
metal walls of transceiver module housing assembly 82, which acts
as a heat sink to further facilitate heat transfer to the
airflow.
[0037] As illustrated in FIG. 7, in another exemplary embodiment an
optical transceiver module system 86 includes at least one
transceiver module 88 and a module cage 90 mounted in a front panel
(wall) of an outer enclosure 92. Fan 36 (FIG. 2) is mounted within
outer enclosure 92 but not shown in FIG. 7 for purposes of clarity.
As shown in FIG. 8, the rear wall of module cage 90 has a grille 94
or array of apertures to admit airflow in the manner described
above with regard to FIG. 2. Transceiver module 88 and module cage
90 more specifically embody or implement the generalized
transceiver module 24 and module cage 28, respectively, described
above with regard to FIG. 2.
[0038] In operation, the airflow enters module cage 90 (FIG. 8)
through grille 94 as described above with regard to FIG. 2. As
further illustrated in FIG. 9, the rear or tail end of transceiver
module 88 has a grille 96 or array of apertures. The opening
defined by grille 96 has an air flow axis aligned in a direction
corresponding to the longitudinal axis 97 (FIG. 8). The airflow
enters the transceiver module housing assembly 98 through grille
96. The air flows through the interior cavity of transceiver module
housing assembly 98 in a direction substantially corresponding to
longitudinal axis 97. As the air flows through the interior cavity
of transceiver module housing assembly 98, the air passes an
electronics subassembly that includes an opto-electronic
subassembly 100 mounted on a PCB substrate 102. Opto-electronic
subassembly 100 includes a light source 101, such as a laser. The
operation of light source 101 causes opto-electronic subassembly
100 to become hot and radiate heat into the surrounding air. The
airflow carries away some of this radiated heat and expels it
through several openings at the nose end of transceiver module 88
that are oriented in different directions from one another.
[0039] As further illustrated in FIG. 9, one such opening in
transceiver module housing assembly 98 from which air is expelled
is defined by a grille 104 or array of apertures in the top or
upper portion of transceiver module housing assembly 98 at the nose
end of transceiver module 88. The opening defined by grille 104 has
an air flow axis 106 aligned in a direction transverse to
longitudinal axis 97. Air is thus expelled in an upward direction,
away from the top or upper portion of transceiver module housing
assembly 98.
[0040] As illustrated in FIG. 10, another such opening in
transceiver module housing assembly 98 from which air is expelled
is defined by a grille 108 or array of apertures in the front or
forward portion of transceiver module housing assembly 98 at the
nose end of transceiver module 88. The opening defined by grille
108 has an air flow axis corresponding to longitudinal axis 97. Air
is thus expelled in a forward direction, away from the front or
forward portion of transceiver module housing assembly 98.
[0041] As further illustrated in FIG. 11, yet another such opening
in transceiver module housing assembly 98 from which air is
expelled is defined by a grille 110 or array of apertures in the
bottom or lower portion of transceiver module housing assembly 98
at the nose end of transceiver module 88. The opening defined by
grille 110 has an air flow axis 112 aligned in a direction
transverse to longitudinal axis 97. Air is thus expelled in a
downward direction, away from the bottom or lower portion of
transceiver module housing assembly 98.
[0042] Referring again to FIG. 8, a driver integrated circuit 114
is mounted on PCB substrate 102. As persons skilled in the art
understand, driver integrated circuit 114 provides electrical
signals to the light source of opto-electronic subassembly 100 in
response to signals received from the external electronic system
within outer enclosure 92. Heat radiating from driver integrated
circuit 114 into the surrounding air is also dissipated from the
interior cavity of transceiver module housing assembly 98 by the
above-described airflow. A heat sink 116 attached to the top of
driver integrated circuit 114 facilitates heat transfer to the
airflow.
[0043] An opening or aperture 118 in PCB substrate 102 allows some
air to flow from a first side of PCB substrate 102 to a second side
of PCB substrate 102. It is this airflow that exits transceiver
module housing assembly 98 through grille 110 (FIG. 11). Driver
integrated circuit 114 is coupled through a thermally conductive
path through PCB substrate 102 to the metal lower wall of
transceiver module housing assembly 98 (including grille 110),
which acts as a heat sink to further facilitate heat transfer to
the airflow. Thus, the airflow that crosses to the second side of
PCB substrate 102 primarily serves to dissipate heat generated by
driver integrated circuit 114, while the airflows that remain on
the first side of PCB substrate 102 primarily serve to dissipate
heat generated by light source 101.
[0044] As illustrated in FIG. 12, in yet another exemplary
embodiment an optical transceiver module system 120 includes at
least one transceiver module 122 and a module cage 124. Although
not shown in FIG. 12 for purposes of clarity, as in the other
embodiments fan 36 (FIG. 2) is mounted within an outer enclosure in
which module cage 124 is mounted. As shown in FIG. 12, the front
wall of module cage 124 has a grille 128 or array of apertures
immediately above each module bay 130.
[0045] As illustrated in FIG. 13, the rear wall of module cage 124
has a grille 132 or array of apertures in a rear wall 134 to admit
airflow in the manner described above with regard to FIG. 2.
Transceiver module 122 (FIG. 12) and module cage 124 more
specifically embody or implement the generalized transceiver module
24 and module cage 28, respectively, described above with regard to
FIG. 2.
[0046] As illustrated in FIG. 14, a number of connectors 136 are
arrayed along the rear wall 134 (removed in FIG. 14 to reveal the
interior of module cage 124). As further illustrated in FIGS.
15-16, each connector 136 comprises an upper connector 138 and a
lower connector 140. Referring again to FIG. 12, when a transceiver
122 is plugged into a module bay 130 of an upper row of module bays
130, the tail end of transceiver 122 is received in upper connector
138. Likewise, when a transceiver 122 is plugged into a module bay
130' of a lower row of module bays 130, the tail end of transceiver
122 is received in lower connector 140. Upper and lower connectors
138 and 140 include spring finger arrays 142 and 144 (FIG. 16),
respectively, which mate with conductive pads at the tail end of
transceiver 122.
[0047] Spring finger arrays 142 and 144 and a contact pin array 146
(FIG. 15) define opposing ends of an array of electrical
conductors. Portions of this array of electrical conductors, such
as portions of spring finger arrays 142 and 144 and contact pin
array 146, are embedded in a material (e.g., plastic) from which
connector 136 is primarily made. However, an exposed section or
conductor portion 148 of this array of electrical conductors
between upper connector 138 and lower connector 140 is exposed in
an opening 150 (FIG. 16) in connector 136. That is, opening 150
extends between the front and rear of connector 136, and the
exposed conductor portion 148 spans opening 150 from one of its
edges to an opposite edge. Note that air can flow relatively
unimpeded between the front and rear of connector 136 through the
interstitial spaces (between adjacent conductors) of exposed
conductor portion 148 where the conductors span opening 150 and
thus flow through opening 150.
[0048] As illustrated in FIG. 17, portions of spring finger arrays
142 and 144 and contact pin array 146 are embedded in a material
such as plastic to define a planar connector structure 152. In
forming connector 136, planar connector structures 152 are stacked
next to each other like books on a shelf.
[0049] In operation, the airflow enters module cage 124 (FIGS. 13
and 19) through grille 132 in the manner described above. As
illustrated in FIG. 18, transceiver module 122 has a first opening
154 in the upper wall of the transceiver module housing assembly
156 at the rear or tail end of transceiver module 122 and a second
opening 158 in the upper wall of transceiver module housing
assembly 156 at the front or nose end of transceiver module 122.
The airflow enters transceiver module housing assembly 156 through
first opening 154. As indicated by arrows in FIG. 19, the air flows
through the interior cavity 159 of transceiver module housing
assembly 156 in a direction substantially corresponding to the
longitudinal axis 160. As the air flows through interior cavity
159, the air passes an electronics subassembly that includes an
opto-electronic subassembly 162 mounted on a PCB substrate 164.
[0050] An enlarged portion 165 of FIG. 19 is shown in FIG. 20.
Opto-electronic subassembly 162 includes a light source 166, such
as a laser. The operation of light source 166 causes it to generate
heat. Light source 166 is coupled through a thermally conductive
path to a heat sink 168. Light source 166 is mounted on a forward
portion 169 of heat sink 168 beneath opto-electronic subassembly
162. A rearward portion 171 of heat sink 168 is mounted within
interior cavity 159 on PCB substrate 164 rearward of
opto-electronic subassembly 162. In operation, heat generated by
light source 166 is conducted from forward portion 169 of heat sink
168 to rearward portion 171 of heat sink 168. The incoming air
flows past rearward portion 171 of heat sink 168. The airflow
carries away some of the heat radiated by heat sink 168 and expels
it through second opening 158 at the nose end of transceiver module
122. Note in FIG. 18 that first and second openings 154 and 158
have flow axes 176 and 178, respectively, oriented transversely to
longitudinal axis 160. After exiting transceiver module housing
assembly 156 through second opening 158, the air flows out of
module cage 124 through grating 128, which has a flow axis 180
(FIG. 19).
[0051] Returning to FIG. 20, a driver integrated circuit 170 within
opto-electronic subassembly 162 is mounted on and electrically
connected to PCB substrate 164 (electrical connections are not
shown for purposes of clarity). A number of thermal vias 172 (i.e.,
thermally conductive plated through-holes) in PCB substrate 164
conduct heat from driver integrated circuit 170 to the lower wall
of transceiver module housing assembly 156. As transceiver module
housing assembly 156, serves as a heat sink by radiating the heat
generated by driver integrated circuit 170 to the environment
outside transceiver module housing assembly 156. It can be noted
that in this embodiment there are two thermal paths: a first path
in which heat generated by light source 166 is radiated by heat
sink 168 and carried out of transceiver module housing assembly 156
by the airflow; and a second path in which heat generated by driver
integrated circuit 170 is conducted to transceiver module housing
assembly 156 and radiated to the exterior environment. Providing
separate thermal paths for light source 166 and driver integrated
circuit 170 can be advantageous because it allows driver integrated
circuit 170 to operate at a higher temperature than light source
166. Driver integrated circuit 170 commonly generates much more
heat than light source 166 (e.g., a VCSEL) and is more tolerant of
excess heat than light source 166. Providing two separate thermal
paths for light source 166 and driver integrated circuit 170
inhibits the excess heat generated by driver integrated circuit 170
from adversely affecting the operation of light source 166.
[0052] One or more illustrative embodiments of the invention have
been described above. However, it is to be understood that the
invention is defined by the appended claims and is not limited to
the specific embodiments described.
* * * * *